Electronic communication systems continually strive to communicate information in a reliable and efficient manner. The amount of information that can be communicated over a given bandwidth in the presence of noise is bounded by the Shannon limit. Most communication system utilize coding and modulation schemes that do not come close to approaching the Shannon limit.
A communication system may tradeoff complexity for efficiency. The communication systems that utilize encoding schemes that more closely approach the Shannon limit typically require more signal processing compared to communication systems implementing simpler encoding schemes.
A communication system designer typically examines a number of factors when selecting the type of encoding and modulation used within a system. Ideally, the communication system will be robust and offer satisfactory performance over various operating conditions. Other factors, such as spectral efficiency and spectral occupancy may need to be constrained in order to meet system requirements.
It is desirable to have a communication system that is spectrally efficient in order to maximize the amount of information that is communicated. Additionally, it is desirable to implement an energy efficient waveform, such that the amount of signal required to achieve a prescribed performance level can be minimized.